Dynamic light scattering microrheology for soft and living materials

We present a method for using dynamic light scattering in the single-scattering limit to measure the viscoelastic moduli of soft materials. This microrheology technique only requires a small sample volume of 12 mu L to measure up to six decades in time of rheological behavior. We demonstrate the use of dynamic light scattering microrheology (DLS mu R) on a variety of soft materials, including dilute polymer solutions, covalently-crosslinked polymer gels, and active, biological fluids. In this work, we detail the procedure for applying the technique to new materials and discuss the critical considerations for implementing the technique, including a custom analysis script for analyzing data output. We focus on the advantages of applying DLS mu R to biologically relevant materials: breast cancer cells encapsulated in a collagen gel and cystic fibrosis sputum. DLS mu R is an easy, efficient, and economical rheological technique that can guide the design of new polymeric materials and facilitate the understanding of the underlying physics governing behavior of naturally derived materials.

Automated summary

The method presented involves using dynamic light scattering to measure the viscoelastic moduli of soft materials in the single-scattering limit. It requires only a small sample volume and can measure up to six decades in time of rheological behavior. This microrheology technique has been successfully applied to various soft materials, proving to be easy, efficient, and cost-effective for guiding new material design and enhancing understanding of naturally derived material behaviors.